JPH02209985A - Method and composition for improving energy efficiency in heat pump system - Google Patents

Abstract

PURPOSE: To improve the energy efficiency of a heat pump system such as a cooling unit or a heating and air-conditioning system by introducing a liq. polar compd. in operating a heat pump.

CONSTITUTION: In operating a heat pump such as a reciprocating or rotary compressor, a liq. polar compd., pref. comprising a liq. chlorinated α-olefin, a liq. chlorinated paraffin, etc., is introduced in an amt. of 0.1-10 vol.%, optimally about 1-2.5 vol.% (based on a lubricant). Moreover, a carrier system may be added in an amt. of 5% of the total lubricants.

COPYRIGHT: (C)1990,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improving the energy efficiency of so-called heat pump systems, including refrigeration units, heating and air conditioning systems, etc., which pump heat from one side to another.

BACKGROUND OF THE INVENTION Since the early 1970's there have been continuous efforts to improve the energy efficiency of heating and cooling units operating on the heat pump principle. As is well known, a heat pump functions by the property that energy is absorbed or released when a compressible liquid is pressurized in a compressor or depressurized by a valve, orifice, etc. Generally, these systems rely on the phase change from gas to liquid phase resulting from a pressure change to effect heat transport. Such heat pump units are used in large-scale commercial facilities for refrigerating or freezing perishable items, large-scale commercial buildings, and general household environments. The energy efficiency of these units has been greatly improved through compressor and motor design changes and other mechanical and design improvements. As for compressors, improved methods for lubricating them are being developed to reduce frictional energy, while new compressor designs are also being developed to improve the energy efficiency of the system. However, improvements in energy efficiency continue to be sought in the field of heat pump technology.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to provide a composition that can significantly improve the energy efficiency of a heat pump system.

Another object of the present invention is to provide a composition that helps improve the energy efficiency of both air conditioning units and refrigeration units.

Furthermore, it is an object of the present invention to provide a method for improving the energy efficiency of a heat pump system.

Means for Solving the Problems> The above and other objects of the present invention are to provide a heat pump system with a compound having a polar site in which part of the molecule is in a low electron density state and the other part is in a high electron density state. contains. This is achieved by introducing the 11I compound. The compounds to be added are selected to be those which are 'liquid' at any stage of the heat pump cycle.

Heat pump systems in use today typically transport heat from one side to another using a compressible liquid.
ing. The most common heat transport media are freons and ammonia. Ammonia is used inter alia in large scale cooling systems such as cold storage units. In addition to these two groups, other compressible liquids whose phase changes in response to a considerable pressure change can be used as heat transport medium or compressible liquid. Compressible liquids that change phase from a liquid phase to a gas phase in response to changes in pressure are well known in the art, and carbon dioxide is one of them. - The selection of a heat transport medium for boat fishing is determined by considering many design criteria, and these design criteria are also well known. Freon or ammonia are usually the most preferred heat transport media in commercial-scale installations;
Media such as carbon dioxide are also used in special equipment.

The polar organic compound of the present invention has one region of the molecule with high electron density,
Contains sufficient polar groups to provide an intramolecular electronic region where other regions have low electron density.

Naturally, the selected compound must be compatible with the compressible liquid as the heat transport medium and with the materials constituting the various parts of the heat transport system. Furthermore, the compounds to be used must remain essentially liquid during operation of the system. That is, substantially no solidification should occur in the cold or expansion section of the heat pump system, and vaporization should be minimal on the high pressure side of the system, even at high temperatures. In other words, the polar compound must be essentially incompressible under system operation. In addition to being compatible with both the heat transport medium and the materials of construction of the heat pump system, the polar compound must also be compatible with the lubricant used in the heat pump system. As is well known, heat pump systems utilize lubricants that are continuously circulated through the system to lubricate the moving parts of the compressor.

Typically these lubricants are based on naphthenic oils. The most common lubricants are 3GS and 4GS
It is a cooling oil called. In the practice of the present invention, essentially all polar compounds that meet the following criteria can be used.

The polar compounds used in the present invention are liquid halogenated alpha-olefins and liquid halogenated paraffins, particularly those in which the halogen is chlorine. The most preferred polar compounds are liquid chlorinated alpha-olefins. Liquid chlorinated alpha-olefins are preferred for use in cooling systems, particularly for food preservation, because of their good carcinogen activity test results. Thus, refrigeration systems containing liquid chlorinated alpha-olefins are useful for food preservation.

The liquid chlorinated alpha-olefins and liquid chlorinated paraffins must remain liquid throughout the various operating conditions of the L-pump system. Although the molecular weight and degree of chlorination of these materials are not particularly critical, it is necessary to avoid using materials with a high wax content, which can solidify in the expansion section of the heat pump system.

These high-wax substances can accumulate on the system's valves and the like, causing breakdowns and increased maintenance. Furthermore, the presence of these solid components can be an obstacle to achieving the desired energy efficiency improvements. As a typical representative, both liquid chlorinated alpha-olefins and liquid chlorinated paraffins contain 6 to 24 carbon atoms and 1 to 12, preferably 1 to 10, chlorine atoms. The degree of chlorination and molecular weight determine the relative volatility and solidification point of the compound. Particularly preferred among the chlorinated alpha-olefins is the product name Chlor from Diamond Shamrotsuta Co., Ltd.
There is one sold as omax-500AO, which is C+Ji. It is a chlorinated alpha-olefin with the chemical formula C1m. Preferred chlorinated liquid paraffins include those available from Diamond Jamrock under the trade names Chlorowax 5760 and Chlo
There is one sold as rowax 5960.

Chlorowix 5760 has one binding C+sL*C1
m, while Chlorowax 5960
is expressed by one binding margin C+*H,,Ct.

Other chlorinated alpha-olefins and chlorinated paraffins used in the present invention have electron densities selected such that one portion of the compound molecule has two regions of high electron density and the other portion of the compound has low electron density. It is a polar compound. High and low electron density are relative, and the difference in degree of chlorination between the two regions does not need to be large. The important point is that there is a charge distribution within the molecule.

Polar compounds are believed to physically adhere to the metal walls of heat pump systems due to their polarity. The metal surfaces of heat pump systems are believed to have a high charge such that polar molecules align with them and form metal surface van der Waals bonds. Although it is not a specific theory, when a polar compound is attached to a metal wall, this suppresses the thermal phase phenomenon that occurs when the liquid inside the tube is transferred to the surrounding liquid through the tube wall. bring about an effect. This boundary phase phenomenon reduces the heat transport coefficient and further leads to a reduction in efficiency.

From the results of the experiments carried out to date, it appears that the use of the above polar compounds can significantly reduce the problems posed by boundary phase phenomena.

Experiments have shown that not only is the energy consumption lower, but the transfer of heat between the surfaces where heat transport takes place is substantially increased. Such improved heat transport is manifested as an increase in the heat transport coefficient of the system and a shortened system cycle. As a result of improved heat transport, power consumption is significantly reduced in heat pump systems. Energy can also be saved by increasing heat transport,
Furthermore, by reducing the size of the entire heat pump system relative to a given load, a smaller compressor can be used, which can further improve thermal efficiency.

The amount of polar compound to be used in the heat pump system in the present invention need only be sufficient to increase energy efficiency by the desired amount. Generally, improved energy efficiency cannot be obtained immediately by adding a polar compound; there is a time delay until the compound is dispersed throughout the system. The length of this delay depends on the amount of polar compound added to the system. The amount of polar compound therefore depends on the size of the system and how quickly the compound is desired to disperse within the system. Generally, the amount of polar compound will depend on the volume of lubricant used in the system. The proportion of polar compounds is generally 0.1 vol of lubricating oil.
1% to 10vol%, preferably 0.5vol% to 5
vo1%. More preferably, the amount of polar compound is about 1-2.5% vol. of the total lubricant volume. Preferably, the polar compound is soluble in the lubricant present in the system at the concentrations in which it is used. That is, the solubility of the polar compound is preferably greater than its concentration in the lubricating oil. In addition to the physical and chemical properties described above, the polar compound must be compatible with the lubricating oil.

There are no particular restrictions on introducing polar compounds into the heat pump system. It can be added to the lubricating oil when assembling the system, and it can also be added to the lubricant during system operation. If polar compounds are added during system operation, they are typically injected into the suction side of the compressor. In a particularly preferred embodiment, the polar compound is first dissolved in a carrier compound to form a concentrated solution to facilitate its injection (and to better control the volume to be added).

Generally, the carrier component can be any component that is compatible with heat pump systems. Typically, the carrier contains a lubricant used to lubricate the system. More preferably, the carrier is white oil, high purity naphthenic mineral oil. Such white oils are commonly commercially available, such as materials such as Texaco Capellal IP or equivalents thereof. The use of white oil has the advantage of being essentially compatible with any heat pump system, including both refrigeration and air conditioning. Cooling systems have the most severe requirements because of their low temperatures. The one-body compound must be liquid throughout the entire heat pump cycle and must be substantially free of waxes that solidify during operation. The use of white oil as a carrier has the advantage that a single composition containing polar compounds can be used in essentially any heat pump system.

Although the concentration of polar compounds in the carrier is not a determining factor, 20
~8.(1 vol.), typically a roughly equal volume mixture.

A carrier system containing an equal volume mixture of polar compound and carrier,
5% of the total lubricant contained in the system can be added to the existing oil system. The proportion at which it is added can be larger or smaller depending on the concentration of polar compound in the carrier material and the desired final concentration of polar compound in the heat pump system.

When using halogen-containing polar compounds, it is preferred to use stabilizers to prevent moisture in the system from forming free halogens. The presence of free halides causes corrosion problems. Suitable stabilizers for chloride are commercially available buffers that typically bind to the halogen and render it harmless. Such stabilizers are sold by many companies, such as Diamond Shamlottuta's X-Ch for-XC, which is a mixture of chlorinated hydrocarbons, white mineral oil, humectants and inhibitors. Other commercially available compounds containing halogen inhibitors can be used as well. The amount of stabilizer is not a critical factor, but for polar compounds 0-20
vo1%, preferably 0. O1 to 20vol%, more preferably 0.01 to 10vol%. Any stabilizer may be used as long as it functions as a buffer for free chloride, is compatible with polar compounds and lubricants, and is dissolved during operation.

EFFECTS OF THE INVENTION Experiments to date have shown that the compositions and methods of the present invention can improve the energy efficiency of heat pump systems based on both reciprocating and rotary compressors. Substantial improvement in energy efficiency from unit size of 1 ton to 800 ton
Obtained ranging from tons of stuff. In addition, according to the present invention, 10
An improvement in energy consumption of more than % was achieved.

<Example> The present invention will be further explained with reference to Examples below.

The following tests were conducted using a York Model 354 water-cooled self-contained air conditioner. This model has a cooling capacity of 3.
The 3 ton, Chlorowax 500^0 intensification process was carried out using a 30 horsepower compressor driven by a 208/220 volt, 3 phase, 60 hertz motor. These tests were conducted in an approximately 7200 cubic foot laboratory.

1. Equipment selection Manufacturer's original capacitor, expansion
A well-used hermetic seal compressor equipped with a valve, evaporator, right hand and Freon R-22 control system was chosen specifically for this experiment. The units tested were purchased and first used in 1962.

This unit contained 0.875 gallons of Yoke "C" oil as a hermetic seal lubricant. Table 1 shows a comparison between the data measured in this test and the manufacturer's initial rating values.

Margin 2 below, Motor Monitoring KVA Demand, KW, and Reactivity KVA (or KV
Esterine-Angus S-22904 with 3-venn capacity for continuous recording of AR) and readout capability for instant KVA and power factors.
A monitoring device consisting of a mini servo power survey unit was used.

Also, a resettable counter was used that indicates the cumulative ηH oil consumption whenever the motor is energized. A clamp-on current transformer was used to reduce the full line amperage of each of the three phases of the motor by a factor of 100 upon transfer to the recording wattmeter.

3. Addition IJI of Chlorowax-500AO
□ Rowax fluid was injected into the hermetic seal lube system. Gas check valves were installed in each of the high-pressure liquid Freon system from the compressor and the low-pressure Freon vapor system leading to the compressor suction port. When the compressor is running, these valves contain 15+nl of liquid Chlor
It was used to collect small amounts of high pressure Freon in a copper cartridge containing owax. The pressurized cartridge was then disconnected from the high pressure side of the compressor and its contents were introduced into the low pressure Freon vapor system by a suitable needle valve arrangement and returned to the compressor suction in the refrigerant flow. Approximately 5 vo1% Chlorowax and 9
15 ml was selected as an amount to eliminate the 180 ml that ultimately required addition to the lubrication system as 5 vol. 1% oil. That is, the injection was repeated 12 times during the experiment in 15 ml portions.

4. Cooling load test The cooling load applied to the air conditioning unit varied depending on the outside temperature. The laboratory to be cooled was disconnected from the building's normal temperature control system.

Temperatures within the building during testing ranged from 77°F to 84” in the hallway, attached lab, and labs directly above and below the lab.
F (soft ball/DB), 69@F to 74”F (wet ball/W
B). The laboratory air conditioning thermostat was set at 71°F throughout the test, and this setting kept the laboratory huff from 0 to 7 rF (11B) throughout the entire measurement period.
and 64-65°F (11B).

The cycle time at thermostat setting 73°F also affects the cooling capacity of the unit.
After testing the effectiveness of the owax 2.5valX/oil 97.5% ratio, it was investigated for calibration.

These conditions necessitated a modified yoke 354 unit to eliminate the substantial heat gain obtained in the laboratory. External wall (
and the presence of windows), the external temperature is 71
``Natural heat loss occurs when the outside temperature is below F, and adds to the indoor heat gain when the outside temperature is above.'' (7) The performance of the sky 11 units showed a similar energy consumption pattern varying with the solar and weather conditions.Thus, the test system was tuned according to the solar and weather conditions.

Results Table 3 shows the daily energy consumption of the compressor motor for each cooling day hour in the air conditioning unit. These data are C on each date shown in Table-2.
Obtained following injection of hlorowax.

Table 3 below shows daily data regarding the WH and day hours consumed by the margin compressor motor.

The following margins are measured from 12:00 pm to 12:00 pm the following night, based on central standard time. The daily variation in KWH is that the motor is energized (by the thermostat signal)
Rather than measuring line current or measuring wattage change when
Results of changes in total cycle time over 4 hours.

The output to the motor is basically 2. ．． It was constant at 79KW. The thermostat setting was fixed at 71°F throughout this test. As a result of this test, Chloro
-WJIX is 4. ? It can be seen that vo1% is the optimum concentration.

Obviously, many variations and modifications of the present invention are possible in light of the above disclosure. Therefore, within the scope of the appended claims, other implementations than the specific examples described herein are possible.

that's all

Claims (1)

[Scope of Claims] 1. A method for improving the efficiency of a heat pump system, characterized by introducing a polar compound that is in a liquid state into the heat pump system during operation of the heat pump. 2. A method for improving the efficiency of a heat pump system, comprising using a polar compound present in liquid form throughout the heat pump system in an amount sufficient to improve the energy efficiency of the system. 3. A heat pump system additive characterized by containing a polar compound and a liquid carrier. 4. The method according to claim 1, wherein the polar compound is a halogenated alpha-olefin or a halogenated paraffin. 5. Process according to claim 1, characterized in that the polar compound is a chlorinated alpha-olefin or a chlorinated paraffin. 6. Process according to claim 1, characterized in that the polar compound is a halogenated hydrocarbon having 6 to 24 carbon atoms and 1 to 12 halogen atoms. 7. The method according to claim 1, wherein the polar compound has a chemical formula of C_1_2H_2_0Cl_6. 8. The method of claim 1, wherein the heat pump system contains a lubricant, and the polar compound is present in an amount of 0.1 to 10 vol% of the volume of the lubricant. 9. The additive according to claim 3, wherein the liquid carrier is white oil. 10. The additive according to claim 3, wherein the polar compound is a liquid halogenated alpha-olefin or a halogenated paraffin. 11. The additive according to claim 10, wherein the polar compound is a liquid chlorinated alpha-olefin represented by the chemical formula C_1_2H_2_0Cl_6. 12. The additive according to claim 11, which contains a buffering agent. 13. The additive according to claim 3, wherein the carrier is naphthenic oil.